Prevent a user from deleting, moving or renaming a file

Question

What I am trying to do is while my program is using a file, I want to keep the user from renaming, deleting, or moving the file (well... a move is a delete and a create at a different location according to Windows FileSystemWatcher, but I digress).

It has been suggested that I use FileStream.Lock or use a Mutex. However, FileStream.Lock seems only to prevent the file from being modified which I am trying to allow. Also, I am very unsure as to if a mutex can lock a file, although I am still reading on it with in the .Net 4.0 library.

Does anyone have any advice on utilizing either one and if there is a code based solution to this problem?

Answer 1

When you are opening the file, you can specify the sharing mode.

Opening the file with FileAccess.Read gives you the ability to read the file, while FileShare.ReadWrite allows the file to continue to be edited, but not deleted or moved.

var fs = File.Open(@"C:\temp\file.txt", FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
MessageBox.Show("File Locked");  // While the messagebox is up, try to open or delete the file.
// Do your work here
fs.Close();

Answer 2

This will prevent moving or deleting the file but allows read and write:

    using (FileStream fs = new FileStream(@"C:\TestDir\Test.txt", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        // Do Stuff.
    }

FileStream.Lock is actually a range lock which prevents modification of a particular portion of a file while the lock is held.